Molten metal pouring device having pantograph tilting mechanism

ABSTRACT

A metallurgical casting furnace for pouring one or a plurality of horizontally spaced molds. System utilizes a cradle which is adapted to arcuately position a crucible for pouring while allowing either horizontal or vertical ingot charging. A pantograph tilting mechanism permits the crucible to be retained in upright position during arcuate displacement and is also adapted to tilt the crucible independently for teeming into one mold at a time. Vacuum, air melt or controlled atmosphere environments may be employed.

United States Patent [1 1 Richman MOLTEN METAL POURING DEVICE HAVINGPANTOGRAPII TILTING v MECHANISM [75] Inventor: Jay Leivis Richman,Philadelphia,

[73] Assignee: Pennwalt Corporation, Philadelphia,

[22] Filed: Nov. 12, 1971 21 Appl. No.: 198,360

[52] US. Cl. 222/166, 164/136 [51] Int. Cl 822d 37/00 [58] Field ofSearch 222/165, 166, DIG. 8;

[56] v References Cited UNITED STATES PATENTS 3,393,837 7/1968Takeshima... 222/166 521,519 6/1894 Adams 222/165 [4 1 July 24, 1973FOREIGN PATENTS OR- APPLICATIONS 143,082 10/1930 Switzerland 222/166404,496 Germany 222/166 Primary Examiner-Robert B. Reeves AssistantExaminer-David A. Scherbel Attorney-Stanley Bilker [57] ABSTRACT Ametallurgical casting furnace for pouring one or a plurality ofhorizontally spaced molds. System utilizes a cradle which is adapted toarcuately position a crucible for pouring while allowing eitherhorizontal or vertical ingot charging. A pantograph tilting mechanismpermits the crucible to be retained in upright position during arcuatedisplacement and is also adapted to tilt the crucible independently forteeming into one mold at a time. Vacuum, air melt or controlledatmosphere environments may be employed.

5 Claims, 4 Drawing Figures PATENIEBJULZMSB SHEET 1 0F 2 lwm r .58

M/VENTOR JAY LEW/S R/CHMAN ATTORNEY mmmmz I 3,741. 808

' m: z or 2 INVENTOR JAY LE WIS R/CHMAN ATTORNEY MOLTEN METAL POURINGDEVICE HAVING PANTOGRAPH TILTING MECHANISM This invention relates to ametallurgical furnace and more particularly relates to a melting furnacewhich is adapted to pour and cast one or more molds under vacuum, air orcontrolled atmosphere environments. The system is especially adaptedvfor molds introduced into a vacuum chamber in horizontally spaceddisposition with each other.

The present invention concerns a research and development furnace forstudies especially directed to vacuum melting and casting of highquality vacuum grade alloys, including the fabrication of directionallysoliditied castings. The instant system is semi-continuous in nature andis particularly adapted to a system in which a mold is elevated into avacuum mold chamber by means of a lift assembly operating within anairlock. After the mold is poured,- provisions may also be made to allowthe mold itself to be withdrawn at a controlled rate within a moldheater, if desired, such that crystal growth can be oriented in apredetermined direction.

It is therefore an object of this invention to provide a metallurgicalcasting furnace in which a furnace crucible may be positioned and tiltedin opposite directions in order to serve a plurality of molds.

Another object of this invention is to provide a vacuum melting furnacein which the crucible may be positioned for either vertical, horizontalor angular charging without requiring alterationin the positioningcradle assembly.

Still another object of this invention is to provide a plural castingvacuum melting furnace in which a single cradle is adapted to hold thecrucible in upright position during melting and/or charging, and afterdisplacement over the various mold positions permit tilting of thecrucible into pouring disposition.

Other objects of this invention are to provide an improved device of thecharacter described that is easily and economically produced which issturdy in construction and both highly efficient and effective inoperation.

With the above and related objects in view, this invention consists ofthe details of construction and combination of parts as will be morefully understood from the following detailed description when read inconjunction with the accompanying drawings in which:

FIG. 1 is a sectional elevational view of a vacuum melting furnace withplural casting means embodying this invention. 4

FIG. 2 is a sectional view taken along lines 2-2 of FIG. 1.

FIG. 3 is a side elevational view, and partly in section, of anotherembodiment of the vacuum melting and casting furnace.

FIG. 4 is a sectional view taken along lines 4-4 of FIG. 3.

melting a charge of metal loaded therein. Electrical power and coolingwater are supplied to the crucible A. through a flexible conduit 12which passes through a seal plate 14 mounted on the vacuum chamber B.

The vacuum chamber B includes a steel water jacketed shell 20 whichhouses the crucible A and a pair of locks 22 and 24 situated therebelowfor loading the molds D into the melt chamber 20 through a flapper valve26 into a pouring position below the crucible. The furnace or crucible Acan be positioned for vertical charging through ingot or slug chargingmechanism 28. As an alternative, horizontal ingot charging may beaccomplished through slug loading mechanism 30 shown in phantom by thebroken lines. The vertical charger 28 (and the horizontal charger 30option, if employed) is equipped with valved evacuation lines and vacuumbreak valves (not shown) to permit repeated use while maintainingchamber vacuum. Regardless of whether vertical, horizontal or angularcharging is selected, the mechanism is capable of loading ingots 4inches to 20 inches in length and from 2% inches to 4 inches indiameter.

The valved ingot charger 28 is designed to reliably place the alloy slugon the bottom of the empty crucible A, including the ability to add aningot to a partially filled crucible containing molten metal. Inaddition to the charging mechanisms, there is also included a valvedport 32 by way of which thermocouple leads (not shown) may be passed fortreating melt temperature. The port 32 may also be employed for a bridgebreaker assembly, as a means for alloy addition, for observation and asa way of sampling the melt.

The tilting mechanism C includes a rotary positioning shaft 34 which isjournaled in bearings 36 and 38 suspended from the roof of the meltchamber 20. The shaft 34 extends through a rotary seal 40 at one end ofthe melt chamber 20 and is rotatably actuated by a drivemotor-gear-reducer system 42. A pair of spaced support arms 44 and 46are rigidly affixed to the shaft 34 as by welding. Trunnions 48 and 50outwardly extending from the crucible A are rotatably journaled inbearings at the lower ends of the respective support arms 44 and 46.Thus, the crucible A is so mounted that it is free to rotate withrespect to the support arms 44 and 46. A sprocket 52 is affixed totrunnion extension 51, and a chain 54 engages sprocket 52 and one side56 of double sprocket 57 in a closed loop. The other side 58 of doublesprocket 57 carries a chain loop 60 which is driven by drive sprocket62. The hub of double sprocket 57 is free to rotate about support shaft34. Tilt drive shaft 64 is keyed to drive sprocket 62 and is rotatablyjournaled in bearing seal 66 mounted in the melt chamber wall 20. Motordrive 68 is adapted to turn shaft 64 upon demand.

For operation during positioning, shaft 34 and support arms 44, 46 arerotated by drive unit 42 so as to arcuately position the crucible, asdesired. The tilting mechanisms (sprocket 52, sprocket 57 and sprocket62 via the chain belts 54 and 60) are held meanwhile in restraint bydrive motor 68 and shaft 64 so that the crucible A itself does notrotate. This serves to maintain the crucible A in an upright position toprevent premature tilting whereby controlled conditions for charging,melting, etc., are achieved. That is, the double sprocket 57 rotatesfreely on support shaft 34 while the latter is turned. Therefore chain54 is free. to wrap and unwrap about sprockets 52 and 56 in the mannerof a parallelogram of forces or a pantograph. However, after thecrucible has been positioned along the arc, the drive 68 may be actuatedso as to rotate the crucible out of its upright vertical position intopouring position at I or I or vertical charging position II (or intohorizontal charging position as at III). With the foregoing arrangement,the crucible A can be positioned and/or tilted in two diametricallyopposed directions to serve two molds.

Referring now to the alternative embodiment of FIGS. 3 and 4, there isshown a modified form C1 of the pantograph positioner in which thepivotal axis of the suspension is located below the level of thecrucible A. In the embodiment C1, the crucible A, the vacuum chamber Band the mold locks 22 and 24 as well as the molds D may be substantiallyidentical to the system shown in FIGS. 1 and 2, or variations may beincluded without departing from the spirit of this invention. As shown,the flapper valves 26 and 27 are shown in closed position, valve 27being also shown in dotted lines to indicate the manner of its beingswung into open disposition to permit passage therethrough of the moldD. The melt chamber B is evacuated through port 70 which is connected toa vacuum pump (not shown) through suitable conduit. Mold heaters 72 and74 are illustrated and permit the molds D to be heated and cooled undercontrolled conditions, such as for directional solidification. A moldlocker door 76 is depicted in leg 24 to show the means in which themolds D are loaded and unloaded into the melting chamber B. A ram orelevator (not shown) is included within each of the legs 22 and 24 forraising the molds D into the melt chamber and then retracting the moldsat a controlled rate from the mold heaters.

The pantograph positioner and tilt mechanism C1 includes a rocker 78rotatably supported with respect to an internal journal 80 and outsidejournal 82. The rocker 78 actually constitutesa sleeve which iscoaxially disposed and freely rotatable about tilt shaft 84, the latterbeing journaled at its right hand end, as shown in FIG. 4, within block86 while the outside periphery of rocker 78 is joumaled within left handbearing 82. Rotary motion for the rocker 78 is provided by a sprocket orcrank 88 which is connected to a suitable drive actuator (not shown),such as by a chain or piston. Rotary motion for the tilt shaft 84 isfurnished by a suitable motor 90. A pair of upstanding arms 91 and 92are fixedly secured to the rocker 78 and constitute a cradle for thecrucible A. Trunnions 94 and 96 out-, wardly extending from the crucibleare pivotally supported in respective bearings in the cradle arms 91 and92. A sprocket 98 secured to the right hand end of trunnion 96 iscoupled by way of a chain 100 to sprocket 102 keyed to tilt shaft 84.

As is apparent from the foregoing description in connection with FIGS. 3and 4, rotation of the crucible A to its desired arcuate position isaccomplished by rotation of rocker 78 through drive 88. Since the rocker78 freely rotates on the now rotatably-fixed shaft 84, the sprocket 98and chain 100 will follow the arcuate position in the manner of apantograph such that the cruelble A can remain upright in all positions.In arcuate position IV with the crucible A upright, the crucible can bevertically loaded by slug or ingot charger 104. In order to pour thecrucible contents into a mold D, the rocker 78 is arcuately turned untilthe crucible is located over the corresponding mold D as in position Vor V. The crucible A is then tilted so as to pour the molten metalthrough the open upper aperture in the mold heater 72 or 74 preparatoryto casting.

Through the use of the pantograph positioning system C or C1, thecrucible A can be oriented very close to the furnace wall B forcharging, thereby reducing the stroke of the charging mechanism andoverall height of the furnace. The crucible can be positioned for eithervertical or horizontal charging without requiring any change in thebasic positioner construction. The centerline of the crucible A alwayscoincides with the centerline of the molds, and this position does notchange throughout the positioning arc. It is also apparent that gearsmay be substituted for the chain and sprocket tilting mechanisms, andother modes of construction may also be employed as well.

Although this invention has been described in considerable detail, suchdescription is intended as being illustrative rather from limiting,since the invention may be variously embodied without departing from thespirit, and the scope of the invention is to be determined as claimed.

What is claimed is:

l. A metallurgical furnace comprising a crucible, trunnions outwardlyextending from said crucible, means constituting a rocker rotatablysupporting said trunnions, said rocker being pivotally supported about aprimary horizontal axis spaced from the axis of said trunnions, firstdrive means for pivoting said rocker so as to arcuately displace saidcrucible in a generally orbital path about the primary horizontal axis,endless loop means constituting a pantograph having one portion thereofrotatably supported freely about the primary horizontal axis and asecond portion thereof coupled in direct rotatable engagement with saidtrunnions, and second drive means integrally coupled in directengagement with said endless loop means for effecting rotation thereof,whereby actuation of said first drive means while said second drivemeans remains unactuated and stationary will cause arcuate displacementof said crucible without effecting tilting thereof and actuation of saidsecond drive means while said first drive means is retained inunactuated disposition will produce tilting of the crucible in the sameplane as the orbital plane of arcuate displacement.

2. The furnace of claim 1 wherein the axis of said trunnions is locatedbelow said axis of said rocker, said pantograph comprising a sprocketcoaxial and rotatable with one of said trunnions, a second sprocket co-.axial with and freely rotatable about the axis of said rocker, and achain inter-connecting said first and second sprockets whereby saidchain and said second sprocket will rotate freely so as to maintain thecrucible upright when said means for pivoting said trunnions isstationary and said means for pivoting said rocker is actuated.

3. The furnace of claim I wherein said rocker constitutes a shaft, asleeve rotatably supported coaxially about said shaft, means forrotating said sleeve, and means for rotating said shaft.

4. The furnace of claim 1 wherein the axis of said trunnions is locatedabove the axis of said rocker.

5. The furnace of claim 4 wherein said rocker constitutesa shaft, asleeve rotatably supported coaxially about said shaft, means forrotating said sleeve, means for turning said shaft, a sprocket coaxialwith and rotatable with said shaft, a second sprocket coaxial with androtatable with one of said turnnions, and a chain interconnecting saidfirst and second sprockets.

t! t t t

2. The furnace of claim 1 wherein the axis of said trunnions is locatedbelow said axis of said rocker, said pantograph comprising a sprocketcoaxial and rotatable with one of said trunnions, a second sprocketcoaxial with and freely rotatable about the axis of said rocker, and achain inter-connecting said first and second sprockets whereby saidchain and said second sprocket will rotate freely so as to maintain thecrucible upright when said means for pivoting said trunnions isstationary and said means for pivoting said rocker is actuated.
 3. Thefurnace of claim 1 wherein said rocker constitutes a shaft, a sleeverotatably supported coaxially about said shaft, means for rotating saidsleeve, and means for rotating said shaft.
 4. The furnace of claim 1wherein the axis of said trunnions is located above the axis of saidrocker.
 5. The furnace of claim 4 wherein said rocker constitutes ashaft, a sleeve rotatably supported coaxially about said shaft, meansfor rotating said sleeve, means for turning said shaft, a sprocketcoaxial with and rotatable with said shaft, a second sprocket coaxialwith and rotatable with one of said turnnions, and a chaininterconnecting said first and second sprockets.